One of the most gruelling tests to which a motor car can be put in the Americas is the climb to the statue of Christ standing at an elevation of 13,500 feet at the crest of the highway over the Andes, between Chile and Argentina.
The journey from Santiago, Eh takes the motor car to altitudes encountered on few other highways i Some ten years ago the Department of Commerce started installing: a series of radio range beacons. Thes ansmit characteristic signals from equivalent loops which interlock and mark the course along the line of equal strength. We have from each important centre two transmitters; One sending the letter N (dash dot) and another one sending at an angle and during the silent intervals of the first one, the letter A (dot dash).
Over a certain area, which represents the beam or "Avenue," these signals interlock with equal strength, so that the pilot hears just one long dash which lasts about five seconds, followed by Morse code letters identifying the station, These signals can be heard about 100 miles except during conditions of bad static.
The pilot flying over such a beam tell at all times whether he is n course" or "off course" to the right or to the left. He cannot tell, however, how far along he has pro-grossed nor how far he is from his destination. If he goes too much "oft course," which may quickly happen with the fast-flying planes of to-day he completely loses his radio guidance.
Improvements have been made by introducing from place to place "radio-marker beacons." These are smaller power beacons, whose principal purpose is to mark intermediate landing fields and also to indicate the intersection points of adjacent range courses. In some eases the; are also used to mark important o outstanding topographical features.
Great improvements have been made lately in the ultra-high frequency band which points toward this part of the spectrum as the one most indicated for flying aids. Series of "curtain beams" or "fans" are about to be put along the main radio-ngo beacons, so as to indicate the approach to ait-ports. These cur-Mains or fans will spread perpendicularly across each of the beams, around the landing stations, such curtains being recognized by a series of dots or dashes on a higher key than those of the main beacons. They will signal to the flier that he is within a few miles of the airport. Right above the airport he will pass over another radio beam spreading like a balloon above it.
Text read from the printed page and cleaned; old type leaves the occasional error.